Immunotherapeutic agents are in general pharmaceutical compositions that are based on the immunology to improve immune functions in patients, thereby treating cancers or infections.
Conventional immunology focused on adaptive immunity existing only in vertebrates, whereas modern immunology has drawn attention to innate immunity, which recently has been recognized as a defense mechanism effective in all living bodies on the earth (Cold Spring Harbor Symp. Quant. Biol., 54, 1-13, 1989. Cell, 91, 295-298, 1997). Lymph nodes are peripheral lymph tissues that lie between lymph ducts, and play the immune responsive roles activating lymphocytes to catch and process foreign materials that invade through skins from outside or tumor cells that grow in the body.
However, such immune responses are induced in not only lymph nodes, but also in other tissues, and therefore the lymph nodes have not been believed an essential tissue for living bodies. Thus, in the light of the fact that cancer metastasis to lymph nodes is a risk factor for cancer patients as is well known, and the prognosis of the patient with cancer metastasis to lymph nodes is drastically different from that of those without such metastasis. In this connection, the lymph nodes have been usually removed without hesitation together with removing a cancer-carrying tissue (radical lymphadenectomy) as a general thing in conventional surgical operations of cancers.
In other words, although radical lymphadenectomy has been known to induce aftereffects bothering patients such as edema or dysmobility, which should be harmful to “Quality of life” of patients to no small extent, those aftereffects have been considered inevitable in compensation for the curing of cancers, and therefore radical lymphadenectomy has been generally conducted in surgical operations.
Radical lymphadenectomy conventionally conducted is advantageous in removal of lymph nodes that may be a risk factor, and capability to reliably diagnose for the stage of cancer patients subjected to the operation. On the other hand, radical lymphadenectomy has disadvantages that it often induces complications such as edema as mentioned above, and that it imposes excessive burdens in operation-time and -procedure on physicians who conduct an operation. The inventor of the present application has considered that the most important disadvantage of radical lymphadenectomy should be the severely adverse effect on innate-adaptive immunity effective in the whole body of patients, which is brought about by removal of lymph nodes that is an important tissue as connection of innate-adaptive immunity, and by discontinuance of lymph ducts that interface between lymph nodes. Such clinical significance of lymph nodes has not been yet recognized in the field of immunology. Additionally, it may be determined waste to remove a cancer-carrying tissue by surgical operation, when the swelling of the lymph node is severe. The present invention could provide a more preferred treatment for such a case.
Further, cancer patients are in general lower in resistance to infections or the like than healthy humans, and specifically cancer patients have significantly lowered immunocompetence not only just after the surgical operation, but also when subjected to chemotherapy, radiotherapy and the like. The invention also provides prevention and therapeutic treatment for such infections as an important purpose.